Systems and methods relating to use of external air for inventory control of a closed thermodynamic cycle system or energy storage system, such as a reversible Brayton cycle system, are disclosed. A method may involve, in a closed cycle system operating in a power generation mode, circulating a working fluid may through a closed cycle fluid path. The closed cycle fluid path may include a high pressure leg and a low pressure leg. The method may further involve in response to a demand for increased power generation, compressing and dehumidifying environmental air. And the method may involve injecting the compressed and dehumidified environmental air into the low pressure leg.

A combined cooling and heating system including a district cooling grid having a feed conduit for an incoming flow of cooling fluid having a first temperature, and a return conduit for a return flow of cooling fluid having a second temperature, the second temperature being higher than the first temperature; a local cooling system being configured to absorb heat from a first building and comprising a heat exchanger having a heat exchanger inlet and a heat exchanger outlet; and a local heating system being configured to heat the first or a second building and comprising a heat pump having a heat pump inlet and a heat pump outlet. The heat exchanger inlet is connected to the feed conduit of the district cooling grid; and the heat pump inlet is connected to the return conduit of the district cooling grid and to the heat exchanger outlet.

A system including: (i) a pumped-heat energy storage system (“PHES system”), wherein the PHES system is operable in a charge mode to convert electricity into stored thermal energy in a hot thermal storage (“HTS”) medium; (ii) an electric heater in thermal contact with the hot HTS medium, wherein the electric heater is operable to heat the hot HTS medium above a temperature achievable by transferring heat from a working fluid to a warm HTS medium in a thermodynamic cycle.

The invention concerns a district energy system comprising: - at least one cogeneration or heat pump unit, - a first pipe system for district heating and/or cooling consisting of at least one liquid or vapor CO.sub.2 pipe; characterized by the fact that is also comprises a second pipe system consisting of at least one fluid line for the transport of CO.sub.2 or O.sub.2. The invention also relates to the use of a district energy system comprising: - at least one cogeneration or heat pump unit, - a first pipe system, - a second pipe system; characterized by the fact that that liquid or vapor CO.sub.2 is used in the first pipe system for district heating and/or cooling and that a fluid of CO.sub.2 or O.sub.2 is used in the second pipe system.

A heat supply system with a first temperature detection unit that detects a first temperature of hot water in a tank, and a second temperature detection unit that detects a second temperature above the first temperature detection unit. When the first temperature is a first lower limit temperature or less, where a temperature increase operation by a combined heat and power supply device is permitted, a control device operates the combined heat and power supply device and flow state adjustment devices such that a heat medium circulates between the combined heat, power supply device, and hot water storage device. When the second temperature is a second lower limit temperature or less, where a temperature increase operation by a boiler device is permitted, the control device operates the boiler device and the flow state adjustment devices such that the heat medium circulates between the boiler device and hot water storage device.

Highly mesoporous activated carbon products are disclosed with mesoporosities characterized by mesopore volumes of 0.7 to 1.0 cubic centimeters per gram or greater. Also disclosed are activated carbon products characterized by a Molasses Number of about 500 to 1000 or greater. Also disclosed are activated carbon products characterized by a Tannin Value of about 100 to 35 or less. The activated carbon products may be further characterized by total pore volumes of at least 0.85 cubic centimeters per gram and BET surface areas of at least about 800 square meters per gram. The activated carbon product may be derived from a renewable feedstock.

A gas turbine includes: a compressor configured to compress air; a combustor configured to combust fuel in the air compressed by the compressor so as to generate combustion gas; and a turbine configured to be driven using the combustion gas. Air coolers are configured to bleed the air from a plurality of places having different pressures in the compressor and cool the air bled from the respective places so as to generate cooling air. A waste heat recovery device is configured to recover waste heat from at least two of the air coolers.

Combined heat and power systems and associated methods are disclosed herein. In some embodiments, the combined heat and power (CHP) system includes a heating appliance, a power cell thermally coupled to the heating appliance and configured to receive a portion of the heat generated by the heating appliance, and power electronics operatively coupled to the heating appliance and the power cell. The power cell can generate a power output from the heat generated by the heating appliance. The power electronics can include a controller configured to detect a loss in external power, and in response enter a blackout operation mode in which the heating appliance is electrically coupled to an energy storage device and/or electrically isolated from an external grid.

A combined heat and power system comprises a shaft (4), a compressor (6) coupled to the shaft to compress intake gas to form compressed gas; a recuperator (10) to heat the compressed gas to form heated compressed gas; a combustor (12) to combust a fuel and the heated compressed gas to form combustion gas; a turbine (8) coupled to the shaft to expand the combustion gas to form exhaust gas; a load (24) coupled to the shaft; an exhaust outlet (18) to expel the exhaust gas to a heater for heating a fluid based on heat from the exhaust gas; a recuperator channel (28) providing a path for the exhaust gas to flow from the turbine to the exhaust outlet through the recuperator; and a bypass channel (22) providing a path for the exhaust gas to flow from the turbine to the exhaust outlet bypassing the recuperator.

An equipment determination method of a cogeneration system includes the steps of: calculating a total hot water supply load for each day over a predetermined period longer than a specific period based on each unit hot water supply load for hour according to hot water supply use by consumers; setting as a representative period a specific period on which the total hot water supply load becomes at least a low load among the calculated total hot water supply load for each day; determining a capacity of the cogeneration equipment based on the total hot water supply load on the set representative period; and determining a capacity of the plurality of hot water storage tanks based on an amount of hot water supply load exceeding the capacity of the determined cogeneration equipment among each unit hot water supply load for two or more divided periods including the set representative period.